Video content programs are commonly supplied to viewers in many different forms, including theater films, video cassettes, TV cable and broadcast systems, game CDs, and on-line networks. Most valuable video content programs (such as first-run or near-first-run feature length films) are distributed to consumers for home viewing on video cassettes, which are rented or purchased from local vendors, or over TV cable or satellite networks on a special premier channels (e.g., HBO.RTM., ShowTime.RTM. or Pay-Per-View.RTM.). With recent technology improvements, video content programs can also be delivered on digital video disks (DVDs) which are the video equivalent to music CDs. Unlike conventional video cassettes which store the video in analog format, DVDs store the video in digital format which results in a higher quality reproduction.
The delivery of valuable video programs to consumers creates a risk of video piracy. Without protection, the video programs can be illicitly intercepted, copied, and redistributed for illegal gain.
One object of this invention is to provide a system and method for the secure delivery of video content programs to consumers for home viewing.
The design issues in developing a secure video delivery system are complicated in that the video content programs can be delivered via many different media. For instance, when the video is distributed over a television cable network to a viewer's set-top box (STB), the focus of security efforts are on preventing unauthorized interception of the video in route to the STB. Traditional design architectures assume that it will be difficult for the viewer to reproduce and distribute the video once it reaches the STB. On the other hand, when the video is distributed on cassette or DVD, the viewer is considered to have the ability to record and redistribute the video with little difficulty. The design effort in this area has therefore been directed to preventing the output data from being copied.
Another object of this invention is to provide a unified video delivery system and method that is versatile to support distribution over many different kinds of media, including networks and DVDs.
In the cable network setting, previous video delivery architectures rely on encryption of the video stream at a headend prior to transmission over the network and use of metering chips located at the STB to limit the number of decryptions performed on the video stream. These metering chips are part of a secret and trusted operating system at the STB. Other architectures employ chips at the STB that require online access to an authorization database prior to decrypting the video stream. However, each of these solutions are highly subject to attack because the STB can be tampered with and patiently reverse engineered until the secret protocols implemented into the operating system are discovered.
It is therefore another object of this invention to provide a secure video delivery system and method that has no global secrets built into any hardware, thereby eliminating the risk that cracking a specific hardware component such as the STB will compromise the entire system.
Despite the best devised plans, protection schemes will inevitably be attacked by pirates who will attempt to circumvent the protection schemes to obtain illegal access to previously distributed videos and new videos as they are released. To minimize the risk of successful attacks, it is desirable to develop protection schemes that are easily replaceable and controllable. In this manner, the video distributors can stay one step ahead of the pirates by replacing protection schemes when or before they are successfully attacked.
Another object of this invention is to provide a secure delivery system that permits easy replacement of the security protocol.
It is also an object of this invention to provide a secure video delivery system that is convenient for consumers to use. The system should grant selective access to paying consumers in a simple, secure manner.